There are several considerations which are utilized in attempting to design a satisfactory tampon. Among these considerations are the prevention of leakage, ease of insertion and removal and ease of manufacturing.
Attempts to meet certain defined objectives amongst these considerations usually produce a lessening of efficacy in obtaining other objectives. For example, the prior art is replete with examples of insertion aids. These aids are usually in the nature of chemicals which provide some form of lubrication to minimize the friction upon insertion. Insertion aids, while performing this function, also form a barrier between the menstrual fluid and the absorbent material with a resultant interference in the efficiency of uptake.
Recently, absorbency characteristics of tampons have been improved by the inclusion of a class of compounds know as "superabsorbents". These materials rapidly absorb fluid and in so doing actually build up a negative pressure at the surface of the absorbent component of the tampons. As a result, when removal occurs extra force is needed to, in essence, tear the tampon away from the vaginal tissue which has been drawn tightly to the tampon surface.
Attempts have been made in the past to minimize this negative pressure by providing either physical or chemical barrier layers between the vaginal tissue and the superabsorbent material. For example, superabsorbent is used as a blend traditionally with more conventional absorbent material. In another approach, an outer wrap capable of retaining fluid has been used (see U.S. Pat. No. 4,056,103).
The tampon of this invention is one which is easily made and due to its unique and unusual construction is easy to insert and withdraw while offering a substantially complete barrier to leakage caused by bypass flow or heavy flow in a short period of time.